Final answer:
A model of criminal punishment where an offender's fixed term can be reduced for good behaviour is called determinate sentencing. Incarceration can be for deterrence or rehabilitation, but its effectiveness varies. Alternatives like community service are often more effective, especially for juveniles and non-violent crimes.
Step-by-step explanation:
A model of criminal punishment in which an offender is given a fixed term that may be reduced by good time or gain time is called determinate sentencing. Incarceration serves various purposes, such as deterrence, incapacitation, and the potential rehabilitation of the offender. Whilst some argue that harsher punishments can act as a deterrent, evidence regarding the effectiveness of prison sentences is mixed. For instance, juvenile incarceration can be counterproductive, possibly leading to higher rates of recidivism. Alternatives such as community service and diversion programs have been noted as more effective, especially for non-violent or less serious crimes.
Punishment and rehabilitation have historically taken different forms, from punitive and often barbarous treatments to more enlightened approaches that emphasize the transformation and restoration of the offender. The practice of determinate sentencing allows for a clear, fixed sentence that can be lessened through good behavior, potentially incentivizing inmates to comply with prison rules and engage in positive activities while incarcerated. However, there is no one-size-fits-all solution in criminal justice, and various approaches may be needed depending on the specific circumstances and types of offenses involved.